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United States Patent | 6,015,720 |
Minegishi ,   et al. | January 18, 2000 |
Method of forming a high-quality polycrystalline semiconductor thin film having large grain sizes by laser annealing. First, a film formation step is carried out to grow a semiconductor layer on an insulating substrate under certain film formation conditions, thus forming a precursory film. This precursory film comprises clusters of microscopic crystal grains. Then, an irradiation step is carried out. That is, the precursory film is irradiated with a laser beam such as an excimer laser pulse. The crystal sizes are increased to change the precursory film into a polycrystalline semiconductor thin film. During the film formation step, a precursory film having a crystal grain size of more than 3 nm is formed at a temperature of 500 to 650.degree. C., for example, by LPCVD or APCVD. Under these conditions, the resulting polycrystalline precursory film is substantially free from hydrogen. During the irradiation step, a single pulse of excimer laser radiation is emitted.
Inventors: | Minegishi; Masahiro (Kanagawa, JP); Ino; Masumitsu (Kanagawa, JP); Kunii; Masafumi (Kanagawa, JP); Urazono; Takenobu (Kanagawa, JP); Hayashi; Hisao (Kanagawa, JP) |
Assignee: | Sony Corporation (Tokyo, JP) |
Appl. No.: | 544569 |
Filed: | October 18, 1995 |
Oct 19, 1994[JP] | 6-280097 |
Current U.S. Class: | 438/30; 257/E21.133; 257/E21.413; 257/E21.703; 438/166; 438/487 |
Intern'l Class: | H11L 021/268 |
Field of Search: | 437/799,173,233,101,109,40 TTF,41 TTF,181,51 257/72 117/8,904 359/59,87 438/30,166,479,482,488,487 |
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TABLE 1 ______________________________________ energy density amorphous silicon polysilicon (mJ/cm.sup.2) (nm) (nm) ______________________________________ 100-200 72 467 200-300 308 523 300-400 34 486 ______________________________________